"Less energy is available due to cold battery" trying to charge

[yobigd20]

car ate 20 miles over 2 nights parked at train station. Had 35 miles when I parked, came back to 12. Fortunately there's a level 2 charger nearby 1/4 mile but it ate 4 miles getting there. Now I'm sitting here on a 30A/240V trying to charge enough to get to a supercharger that is 15 miles away. However it won't charge at a rate higher than 1A. If I turn heat on it'll display 30A being pulled so it's not the charging station. Been sitting here 30 minutes now and it's still showing the same message and it's not gaining any charge....

 

[TexasEV]

You’ve been around long enough to know not to park outside in freezing temperature for two nights with only 35 miles charge.

 

[sorka]

Didn't a recent update allow access to the battery heater like the P models already have?

 

[cmaster]

You can, using the remote app, preheat the car. Preheat the car will turn on the battery heater. For many new owners, they don't know that the the battery heater is the heat that is transferred into the Cabin. I believe they make the assumption that by turning on the heater, it only radiates a heater element near the console.

Also, the battery internal resistance in the cold increases so it needs more energy to do the same amount of work. However, to reduce the battery internal resistance in the cold, you can turn on the heat via the app and this will in turn increase the temperature of the battery. Therefore, it will allow you to charge faster.

 

[AWDtsla]

Didn't a recent update allow access to the battery heater like the P models already have?

No.

 

[sorka]

No.

Here's one thread. There are more.

Battery Pre Heat Available in App now! | Tesla

 

[cmaster]

That is just a UI indicator for those who didn't know how Tesla battery heater worked. It had always been part of the car. And for those who seen the Tesla's patent on the heating system, they know that by turning on the heater does heat the battery. That energy, through convection of the hot air mass, gets pumped into the cabin afterwards.

Here's one thread. There are more.

Battery Pre Heat Available in App now! | Tesla

 

[hiroshiy]

So @yobigd20 , could you tell us what happened next? Hope your car started to charge after one hour or so... Battery heater is 6kW so 240V x 29 = approximately 7kW. You need like 40A or more to charge a very cold battery... You already know this I think though.

 

[AWDtsla]

Here's one thread. There are more.

Battery Pre Heat Available in App now! | Tesla

Fake news. They may have changed the active heating target for the pack by a non-relevant amount. Non-relevant being the key word.

 

[Brass Guy]

Yes, the battery heater will use about 6 kw so almost no power will go into the battery at first. If the battery is cold enough, it wouldn't matter how much power was available from the charging station; it won't charge. Worse yet, if you're sitting there with the cabin heat on too, you're draining the battery further. With the cabin heater plus battery heater; you're using about 12kw and drawing 7 from shore power.

The fastest way to get to the supercharger would be turn the cabin heater off, and make sure range mode is off to ensure the battery heater is on fully. It'll likely take a couple of hours to gain 25 range miles to make it with any margin. With the cabin heater on, you may be there 3 or 4 hours!
Then when you get to the supercharger, it probably won't accept much more than 30 kW until the battery heats up more.

 

[yobigd20]

So @yobigd20 , could you tell us what happened next? Hope your car started to charge after one hour or so... Battery heater is 6kW so 240V x 29 = approximately 7kW. You need like 40A or more to charge a very cold battery... You already know this I think though.

I was on the phone with Tesla for over an hour.

Basically at 10 miles range , the battery was in a 'cold soaked' state, and would only accept a charge rate at 1A until the battery state of charge was > 10%, at which point it would resume a normal rate of charge. There wasn't anything wrong with the charger itself, since when I turned the cabin heat on you could see on the display and on the chargepoint unit that it would jump up to 30A. But turning cabin heat off it falls back to 1A. The power was there. The car just wouldn't use it for normal charging or heating the battery pack.

So I waited 4 hours sitting there charging at 1A, at which point it only accumulated 4 miles now up to 14 miles range. Started at 6:30pm now at 10:30pm , still half the range of what I needed to get to the supercharger at the rate it would eat it. So I found a holiday inn 1.5 miles away that also had an L2 charger. So I headed over there, of course eating 5 miles range to get there. So its back to 9 miles, still cold soaked, and I had to start process all over again and I got a room for the night. It only charged about 1-1.5 miles/hour before it got to 10% around 25 miles and then it kicked up to charging 6-7mph. It basically took about 10-12 hours to get out of this cold soaked state to resume normal charging. Once I had enough charge I left and went to supercharger which charged normally.

I've taken the car down this low before many times but never encountered this state before. The Tesla guy said basically it would only pull this 1A until it got itself out of this state, but that most of that 1A was being used to try and warm the battery. It would not use any more power than that to warm the battery any faster. He was remotely monitoring the car and the battery temps and the temps just would not increase until after the SOC was over 10%, and once that happened then it would use 30A to charge the car.

I've had this car 5 years now, 163k miles, taken it down lower than 10 miles many times. although last month the car did shut down on the highway with 8 miles range left on display. (NO RESERVE PEOPLES....hate it when I see people say 'car has 10-20 miles reserve', just not true. battery range is estimation, and like what happened to me has happened to many the car will shut down even when it shows +range.)

Anyway, throughout 5yr/163k miles never once saw this 'cold soaked state' before where it refused to charge or warm the battery pack until it was over 10% state of charge. this must be new in some recent software update...prettty crappy. I'll have to make sure never to bring the car that low again, and never to leave it parked if its under 50 or so miles range on the display because i dont want to get stuck for 12 hours again.

 

[AWDtsla]

IMHO they brought down the whole temperature vs allowed charge rate map for every pack, making it even harder to get out of being cold soaked "wedged" where you can't get any energy into the car, pack heat or charge - being the most annoying side effect among several.

TL;DR some guy above the arctic circle has a Tesla, so everything is fine.

 

[hiroshiy]

Thanks for the information and explanation from Tesla guy. I have seen reports of cold soaked and very low SOC battery, accepting very low current for charging. Last week I had like 6 degrees Celsius and about 0% battery left. There was a blue frozen sign on the dash. I connected to 64A HPWC and it started to charge at 64A from the beginning.
Maybe the temp is not that low in my case?

Also I wonder what would have happened if you had driven the car a few miles to warm the battery a little bit and charge.

 

[yobigd20]

Maybe the temp is not that low in my case?

Also I wonder what would have happened if you had driven the car a few miles to warm the battery a little bit and charge.View attachment 279288

It was ~20 degrees f. The thing is if I drove it I risked it shutting down. After I drove to the holiday inn it may have charged slightly faster than 1A so your theory might actually be right about driving to warm it up more to get a higher charge rate but that's risky when it's this low range especially when it shut down for me a few weeks ago when 8 miles range was still left on the display. So literally in my head I had a max of 1-2 miles driving range.

 

[rypalmer]

Yet another example of 30A public L2 charging being woefully inadequate for cold climates.

 

[Matias]

I was on the phone with Tesla for over an hour.

Basically at 10 miles range , the battery was in a 'cold soaked' state, and would only accept a charge rate at 1A until the battery state of charge was > 10%, at which point it would resume a normal rate of charge. There wasn't anything wrong with the charger itself, since when I turned the cabin heat on you could see on the display and on the chargepoint unit that it would jump up to 30A. But turning cabin heat off it falls back to 1A. The power was there. The car just wouldn't use it for normal charging or heating the battery pack.

Do you know, why the car didn’t want to warm the battery? I understand, that it didn’t want to charge coald soaked battery, but why the car didn’t want to warm the battery?

 

[Matias]

Yet another example of 30A public L2 charging being woefully inadequate for cold climates.

It wasn’t charger issue. Car didn’t want to take more current. See my quote in the previous post.

 

[rypalmer]

It wasn’t charger issue. Car didn’t want to take more current. See my quote in the previous post.

I realize! But the battery heater alone can saturate a 30A circuit. What about the cabin heater? What about actually charging the car and running the heater concurrently? If you're stranded waiting to a cold charge, you'll want to run the HVAC - trust me.

 

[Matias]

I realize! But the battery heater alone can saturate a 30A circuit. What about the cabin heater? What about actually charging the car and running the heater concurrently? If you're stranded waiting to a cold charge, you'll want to run the HVAC - trust me.

ok

 

[SSedan]

If it ate miles at twice the normal rate it was likely heating the battery, so "range mode" would likely increase economy.

I live near Green Bay and charge my car via 30amp circuit. If the battery is cold soaked warming the battery and interior will for a little while drain miles off the pack even while pulling 24amps, BUT once the pack and interior are warmed it will begin charging, granted I wont get the 19mph I see in summer it will drop to 17 or maybe even a little less but it will work.

This was user error, had you parked it with 80miles and it lost 20 sitting for 2 days with 60miles left it could have warmed the battery while driving to the supercharger.

I learned this lesson in November on my first family roadtrip in the Tesla, Had an early cold snap low single digits told the car to charge to 90% then told it 100% when I got up. Since it had hit 90% 7 hours earlier the pack was cold and the car proceeded to eat a few miles......... Once I got on the road energy use was over 500kwh and car was telling me I wouldn't make the supercharger I picked180miles away so I detoured to catch a supercharger little more than an hour from home but as I drove and the battery warmed energy use came WAY WAY down to like 330, I could have made the supercharger I wanted to but my inexperience led me to commit to a detour that was 30minutes extra drive, besides hitting a supercharger with a fairly full battery which is slow. I didn't bitch as Tesla I learned from my mistakes.

The far end of that trip I only had a 120 15amp circuit to connect to during the day at low single digits, when we left to come home with days of 2mile short hops not warming the battery the battery was stone cold, getting on the highway at 75mph caused the dash to display over 700kwh for the first few miles but it was starting to come down 20minutes later when I got to the supercharger.

I learned a lot on that trip and the wife was upset for a bit worrying about having taken the right car and if we would make it, till I figured out what was going on and explained my mistake.

I do think Tesla could be a little more forthcoming with information on how cold weather can dramatically increase energy consumption, Not anything they could have a calculator or anything for but could use some mention.

I have a short commute one of the reasons I bought a Tesla I was concerned about the fact my old ICE had an 8quart oil system that rarely got warmed up not good for an engine. If I keep range mode OFF so it warms the battery and only preheat for 10minutes plugged in in the morning I can see average energy use 550s till I go for a longer drive and get out of the constant battery heater use. I love the instant heat though, never get that with an ICE.